Display device

ABSTRACT

A display device includes: a substrate; a display unit on the substrate; a first inorganic layer on the display unit; a first organic layer on an upper portion of the first inorganic layer; a first dam at an edge of the first organic layer; a second dam spaced from the first dam and at an outer area of the first dam with respect to the display unit; and a stress relieving layer between the first dam and the second dam.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/582,921, filed Sep. 25, 2019, which is a continuation of U.S. patentapplication Ser. No. 14/832,898, filed Aug. 21, 2015, now U.S. Pat. No.10,454,063, which claims priority to and the benefit of Korean PatentApplication No. 10-2014-0194327, filed on Dec. 30, 2014 in the KoreanIntellectual Property Office, the disclosure of both of which isincorporated herein in its entirety by reference.

BACKGROUND 1. Field

One or more embodiments of the present invention relate to a displaydevice.

2. Description of the Related Art

Along with advancements in information technology, the market fordisplay devices, which are media devices for connecting users withinformation, has expanded. Accordingly, flat panel displays (FPDs), suchas liquid crystal displays (LCDs), organic light-emitting displaydevices, and plasma display panels (PDPs), are widely used.

In such devices, a desire to reduce a dead space region positionedaround a display region is increasing.

SUMMARY

One or more exemplary embodiments of the present invention include adisplay device.

Additional aspects will be set forth, in part, in the description whichfollows and, in part, will be apparent from the description or may belearned by practice of the presented embodiments.

According to one or more embodiments of the present invention, a displaydevice includes a substrate; a display unit on the substrate; a firstinorganic layer on the display unit; a first organic layer on an uppersurface of the first inorganic layer; a first dam at an edge of thefirst organic layer; a second dam spaced from the first dam and at anouter region of the first dam with respect to the display unit; and astress relieving layer between the first dam and the second dam.

The stress relieving layer may include an organic material.

The stress relieving layer may include the same material as that of thefirst organic layer.

The stress relieving layer may be formed using an inkjet process.

The stress relieving layer may be located above the first dam and thesecond dam and may have a height substantially equal to a height of thefirst organic layer.

The display device may further include: a second inorganic layer on anupper surface of the first organic layer.

The display device may further include: a protection film below thesubstrate.

The protection film may be spaced from a display area and may be insidea display area of the display device.

An upper edge of the protection film may be rounded.

The substrate may have a notch, and the notch may be spaced from theedge of the protection film.

The notch may have a triangular shape.

The notch may have a semicircular shape.

The notch may have a rectangular shape.

The stress relieving layer may be between an ELVSS and the second dam.

According to one or more embodiments of the present invention, a displaydevice includes: a substrate; a display unit on the substrate; a firstinorganic layer on the display unit; a first organic layer on an uppersurface of the first inorganic layer; a first dam at an edge of thefirst organic layer; and a stress relieving layer on the substrate at anouter area of the first dam with respect to the display unit.

The display device may further include: a second dam spaced from thefirst dam and at an edge of the stress relieving layer.

The display device may further include: a protection film below thesubstrate.

The protection film may be have a rounded upper edge.

The substrate may have a notch at a lower surface, and the notch may bespaced from the edge of the protection film.

According to one or more embodiments of the present invention, a displaydevice includes: a substrate; a display unit on the substrate; a firstinorganic layer on the display unit; a first organic layer on an uppersurface of the first inorganic layer; a first dam at an edge of thefirst organic layer; and a protection film below the substrate, whereinthe protection film has a rounded upper edge.

The display device may further include: a second dam spaced from thefirst dam and at an outer region of the first dam with respect to thedisplay unit.

The display device may further include: a stress relieving layer betweenan ELVSS and a second dam at an outer region of the ELVSS with respectto the display unit.

The stress relieving layer may include an organic material.

The stress relieving layer may include the same material as that of thefirst organic layer.

The stress relieving layer may be formed using an inkjet process.

The substrate may have a notch in a lower surface of the substrate, andthe notch may be spaced from the edge of the protection film.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects will become apparent and more readilyappreciated from the following description of the embodiments, taken inconjunction with the accompanying drawings, in which:

FIG. 1 is a cross-sectional view of a display device according to anembodiment of the present invention;

FIG. 2 is a cross-sectional view of a display unit according to anembodiment of the present invention;

FIG. 3 is a schematic cross-sectional view illustrating a display deviceaccording to another embodiment of the present invention;

FIG. 4 is a schematic cross-sectional view illustrating a display deviceaccording to another embodiment of the present invention;

FIG. 5 is a schematic cross-sectional view illustrating a display deviceaccording to another embodiment of the present invention; and

FIG. 6 is a schematic cross-sectional view illustrating a display deviceaccording to another embodiment of the present invention.

DETAILED DESCRIPTION

As the present invention allows for various changes and numerousembodiments, exemplary embodiments will be illustrated in the drawingsand described in detail in the written description. Hereinafter, aspectsand features of the present invention and a method for accomplishingthem will be described more fully with reference to the accompanyingdrawings, in which exemplary embodiments of the invention are shown.This invention may, however, be embodied in many different forms andshould not be construed as limited to the exemplary embodiments setforth herein.

Example embodiments of the invention will be described below, in detail,with reference to the accompanying drawings. Those components that arethe same or are substantially similar are indicated by the samereference numeral regardless of the figure number and redundantexplanations thereof may be omitted.

It will be understood that although the terms “first”, “second”, etc.may be used herein to describe various elements, components, regions,layers, or sections, these components should not be limited by theseterms. These terms are only used to distinguish one element, component,region, layer, or section from another. Thus, a first element,component, region, layer, or section discussed below could be termed asecond element, component, region, layer, or section without departingfrom the teachings of example embodiments.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,”“upper,” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” or “over” the otherelements or features. Thus, the term “below” may encompass both anorientation of above and below. The device may be otherwise oriented(rotated 90 degrees or at other orientations), and the spatiallyrelative descriptors used herein should be interpreted accordingly. Asused herein, the terms “use,” “using,” and “used” may be consideredsynonymous with the terms “utilize,” “utilizing,” and “utilized,”respectively.

As used herein, the singular forms “a” and “an” are intended to includethe plural forms as well, unless the context clearly indicatesotherwise.

It will be further understood that the terms “includes,” “including,”“comprises,” and/or “comprising” used herein specify the presence ofstated features or components but do not preclude the presence oraddition of one or more other features or components.

It will be understood that when a layer, region, or component isreferred to as being “formed on” another layer, region, or component, itcan be directly or indirectly formed on the other layer, region, orcomponent. That is, for example, intervening layers, regions, orcomponents may be present. When an element is referred to as being“directly formed on” another element or layer, there are no interveningelements or layers present. It will be understood that when an elementor layer is referred to as being “on”, “connected to”, or “coupled to”another element or layer, it may be directly on, connected, or coupledto the other element or layer or one or more intervening elements orlayers may also be present. When an element is referred to as being“directly on,” “directly connected to,” or “directly coupled to” anotherelement or layer, there are no intervening elements or layers present.For example, when a first element is described as being “coupled” or“connected” to a second element, the first element may be directlycoupled or connected to the second element or the first element may beindirectly coupled or connected to the second element via one or moreintervening elements.

Sizes of elements in the drawings may be exaggerated for convenience ofexplanation. In other words, because sizes and thicknesses of componentsin the drawings may be arbitrarily illustrated for convenience ofexplanation, the following embodiments are not limited thereto.

Although certain embodiments may be described in a certain processorder, a specific process order may be performed differently from thedescribed order. For example, two consecutively described processes maybe performed substantially at the same time (e.g., concurrently orsimultaneously) or may be performed in an order opposite to thedescribed order.

As used herein, the term “and/or” includes any and all combinations ofone or more of the associated listed items. Expressions, such as “atleast one of,” when preceding a list of elements, modify the entire listof elements and do not modify the individual elements of the list. Also,the term “exemplary” is intended to refer to an example or illustration.

FIG. 1 is a cross-sectional view of a display device according to anembodiment of the present invention. FIG. 2 is a cross-sectional view ofa display unit 20 according to an embodiment of the present invention.

Referring to FIG. 1, the display device according to an embodiment ofthe present invention may include a substrate 10, the display unit 20,and an encapsulation unit 30.

The substrate 10 may be formed of a transparent glass materialcontaining, for example, SiO₂ as a main component. However, the materialused to form the substrate 10 is not limited thereto, and the substrate10 may be formed of a transparent plastic material, for example,polyimide (PI).

An array of pixels (or sub-pixels) may be formed in a display area NA ofthe display unit 20 formed on the substrate 10. Each of the pixels mayinclude a thin film transistor and a light-emitting device controlled bythe thin film transistor. The light-emitting device may be aself-emissive-type device, for example, an organic light-emittingdevice.

Only an embodiment in which the display unit 20 is configured as theorganic light-emitting device will be described below for convenience ofdescription, but the present invention is not limited thereto.

The display unit 20 will now be described with reference to FIG. 2.

As shown in FIG. 2, in the display device according to the presentembodiment, a buffer layer 21 may be formed on the substrate 10. Thebuffer layer 21 may act as a barrier layer and/or a blocking layer forreducing or preventing diffusion of impurity ions and penetration ofmoisture or external air and for planarizing a surface of the substrate10.

A semiconductor layer A of a thin film transistor TFT is formed on thebuffer layer 21. The semiconductor layer A may be formed of polysiliconand may include a channel region undoped with impurities (e.g., notdoped) and a source region and a drain region which are each doped withimpurities at respective sides of the channel region. The impurities mayvary depending on the type of the thin film transistor TFT and may beN-type impurities or P-type impurities.

The semiconductor layer A may be formed of a semiconductor includingamorphous silicon or crystal silicon and may be deposited using variousdeposition methods. For example, the crystal silicon may be formed bycrystallizing the amorphous silicon. The amorphous silicon may becrystallized using various methods, such as rapid thermal annealing(RTA), solid phase crystallization (SPC), excimer laser annealing (ELA),metal induced crystallization (MIC), metal induced lateralcrystallization (MILC), and/or sequential lateral solidification (SLS).The semiconductor layer A may be patterned by photolithography.

A gate insulating layer 23 is deposited on the surface (e.g., the entiresurface) of the substrate 10 such that the gate insulating layer 23 maycover the semiconductor layer A. The gate insulating layer 23 may beformed of an inorganic material, such as silicon oxide or siliconnitride, and as a multi-layer or as a single-layer structure. In someembodiments, the gate insulating layer 23 may be formed of siliconnitride (SiN_(x)), silicon oxide (SiO₂), hafnium (Hf) oxide, and/oraluminum oxide. The gate insulating layer 23 may be formed using variousdeposition methods, such as Chemical Vapour Deposition (CVD) and/orPlasma Enhanced Chemical Vapour Deposition (PECVD). The gate insulatinglayer 23 insulates the semiconductor layer A from a gate electrode G.

The gate electrode G may be formed of molybdenum (Mo), aluminum (Al),platinum (Pt), palladium (Pd), silver (Ag), magnesium (Mg), gold (Au),nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), calcium (Ca),titanium (Ti), tungsten (W), and/or copper (Cu).

An interlayer insulating layer 25 is formed on the surface (e.g., theentire surface) of the substrate 10 such that the interlayer insulatinglayer 25 may cover the gate electrode G.

The interlayer insulating layer 25 may be formed of an inorganicmaterial or an organic material. In some embodiments, the interlayerinsulating layer 25 may be formed of an inorganic material. For example,the interlayer insulating layer 25 may be formed of metal oxide or metalnitride. The inorganic material may include, for example, silicon oxide(SiO₂), silicon nitride (SiN_(x)), silicon oxynitride (SiON), aluminumoxide (Al₂O₃), titanium oxide (TiO₂), tantalum oxide (Ta₂O₅), hafniumoxide (HfO₂), zirconium oxide (ZrO₂), or the like. The interlayerinsulating layer 25 may be formed of an inorganic material, such assilicon oxide (SiO_(x)) and/or silicon nitride (SiN_(x)) and as amulti-layer or a single-layer structure. In some embodiments, theinterlayer insulating layer 25 may have a stacked structure ofSiO_(x)/SiN_(y) or SiN_(x)/SiO_(y). The interlayer insulating layer 25may be formed using various deposition methods, such as CVD and PECVD.

The interlayer insulating layer 25 may insulate the gate electrode Gfrom wirings formed on an upper surface of the interlayer insulatinglayer 25.

A source electrode S and a drain electrode D of the thin film transistorTFT are formed on the interlayer insulating layer 25.

A planarization layer 27 is formed on the entire surface of thesubstrate 10 such that the planarization layer 27 may cover the sourceelectrode S and the drain electrode D. A pixel electrode 281 may beformed on the planarization layer 27. The pixel electrode 281 isconnected to the drain electrode D of the thin film transistor TFTthrough an opening VIA (e.g., a via hole).

The planarization layer 27 may be formed of an insulating material. Forexample, the planarization layer 27 may be formed of an inorganicmaterial, an organic material, or a compound including theorganic/inorganic materials. The planarization layer 27 may be formed asa multi-layer or a single-layer structure and may be formed usingvarious deposition methods. In some embodiments, the planarization layer27 may be formed of polyacrylate resin, epoxy resin, phenolic resin,polyamides resin, polyimide resin, unsaturated polyester resin,polyphenylene ether resin, polyphenylene sulfide resin, and/orbenzocyclobutene (BCB).

An organic light-emitting device (OLED) may be formed on the thin filmtransistor TFT. The OLED includes the pixel electrode 281, anintermediate layer 283 including an organic emission layer, and anopposite electrode 285. The OLED may further include a pixel defininglayer 29 and a spacer.

The pixel electrode 281 may be electrically connected to the drainelectrode D of the thin film transistor TFT while filling the openingVIA in the planarization layer 27. The pixel electrode 281 and/or theopposite electrode 285 may be formed as a transparent electrode or as areflective electrode. When the pixel electrode 281 and/or the oppositeelectrode 285 are formed as transparent electrodes, the pixel electrode281 and/or the opposite electrode 285 may be formed of indium tin oxide(ITO), indium zinc oxide (IZO), zinc oxide (ZnO), and/or indium oxide(In₂O₃). When the pixel electrode 281 and/or the opposite electrode 285are formed as reflective electrodes, the pixel electrode 281 and/or theopposite electrode 285 may include a reflective layer that is formed ofsilver (Ag), magnesium (Mg), aluminum (Al), platinum (Pt), palladium(Pd), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium(Cr), or a suitable combination thereof, and a transparent layer that isformed of ITO, IZO, ZnO, and/or In₂O₃. In some embodiments, the pixelelectrode 281 or the opposite electrode 285 may have an ITO/Ag/ITOstructure.

The pixel defining layer 29 may define a pixel region and a non-pixelregion. The pixel defining layer 29 may include an aperture exposing thepixel electrode 281 and may be formed to cover the surface (e.g., theentire surface) of the substrate 10. The intermediate layer 283, whichwill be further described later, may be formed in the aperture, andthus, the aperture may define the entire or substantially the entirepixel region.

The intermediate layer 283 may include an organic emission layer. In oneembodiment, the intermediate layer 283 includes the organic emissionlayer. The intermediate layer 283 may further include a hole injectionlayer (HIL), a hole transport layer (HTL), an electron transport layer(ETL), and/or an electron injection layer (EIL). The present inventionis not limited thereto, and the intermediate layer 283 may furtherinclude the other functional layers in addition to an organic emissionlayer.

The pixel electrode 281, the intermediate layer 283, and the oppositeelectrode 285 together form (e.g., constitute) an organic light-emittingdiode (OLED). Holes and electrons respectively injected from the pixelelectrode 281 and the opposite electrode 285 of the OLED may combinewith each other in the organic emission layer of the intermediate layer283 to thereby generate light.

The HIL may be formed of a phthalocyanine compound, such as copperphthalocyanine, or TCTA, m-MTDATA, or m-MTDAPB which is a star-bust typeamine.

The HTL may be formed ofN,N′-bis(3-methylphenyl)-N,N′-diphenyl-[1,1-biphenyl]-4,4′-diamine(TPD), N,N′-di(naphthalene-1-yl)-N,N′-diphenyl benzidine (a-NPD), etc.

The EIL may be formed of a material such as LiF, NaCl, CsF, Li₂O, BaO,or Liq.

The ETL may be formed of Alq₃.

The organic emission layer may include a host material and a dopantmaterial. Examples of the host material of the organic emission layermay include tris (8-hydroxyquinolinato)aluminum (Alq3),9,10-di(naphth-2-yl)anthracene (AND),3-tert-butyl-9,10-di(naphth-2-yl)anthracene (TBADN),4,4′-bis(2,2-diphenyl-ethene-1-yl)-4,4′-dimethylphenyl (DPVBi),4,4′-bis(2,2-diphenyl-ethene-1-yl)-4,4′-dimethylphenyl (p-DMDPVBi),tert(9,9-diarylfluorene)s (TDAF),2-(9,9′-spirobifluorene-2-yl)-9,9′-spirobifluorene (BSDF),2,7-bis(9,9′-spirobifluorene-2-yl)-9,9′-spirobifluorene (TSDF),bis(9,9-diarylfluorene)s (BDAF),4,4′-bis(2,2-diphenyl-ethene-1-yl)-4,4′-di-(tert-butyl)phenyl(p-TDPVBi), 1,3-bis(carbazol-9-yl)benzene (mCP),1,3,5-tris(carbazol-9-Abenzene (tCP),4,4′,4″-tris(carbazol-9-yl)triphenylamine (TcTa),4,4′-bis(carbazol-9-yl)biphenyl (CBP),4,4′-bis(9-carbazolyl)-2,2′-dimethyl-biphenyl (CBDP),4,4′-bis(carbazol-9-yl)-9,9-dimethyl-fluorene (DMFL-CBP),4,4′-bis(carbazol-9-yl)-9,9-bis 9-phenyl-9H-carbazol)fluorene (FL-4CBP),4,4′-bis(carbazol-9-yl)-9,9-di-tolyl-fluorene (DPFL-CBP),9,9-bis(9-phenyl-9H-carbazol)fluorene (FL-2CBP), and the like.

Examples of the dopant material of the organic emission layer mayinclude 4,4′-bis[4-(di-p-tolylamino)styryl]biphenyl (DPAVBi),9,10-di(naph-2-tyl)anthracene (ADN),3-tert-butyl-9,10-di(naph-2-tyl)anthracene (TBADN), and the like.

The opposite electrode 285 is formed on the intermediate layer 283. Theopposite electrode 285 forms an electric field together with the pixelelectrode 281 so that light is emitted by the intermediate layer 283.The pixel electrode 281 may be patterned for each pixel, and theopposite electrode 285 may be formed so that a common voltage is appliedto all of the pixels.

The pixel electrode 281 and the opposite electrode 285 may be formed astransparent electrodes or as reflective electrodes, or the pixelelectrode 281 and the opposite electrode 285 may separately be formed asa transparent electrode and a reflective electrode. The pixel electrode281 may function as an anode and the opposite electrode 285 may functionas a cathode, but the present invention is not limited thereto. Forexample, the pixel electrode 281 may function as a cathode, and theopposite electrode 285 may function as an anode.

Although only one OLED is illustrated in FIG. 1, a display panel mayinclude a plurality of OLEDs. One pixel may be formed in each of theOLEDs. Each pixel may implement (e.g., output) a red color, a greencolor, a blue color, or a white color.

However, the present invention is not limited thereto. The intermediatelayer 283 may be commonly formed on the entire pixel electrode 281irrespective of locations of pixels. In this embodiment, the organicemission layer may be formed by stacking a light-emitting substance foremitting (e.g., configured to emit) a red light, a light-emittingsubstance for emitting a green light, and a light-emitting substance foremitting a blue light vertically or by mixing them. Any suitablecombination of other colors which is capable of emitting a white lightis possible. The organic emission layer may further include a colorconverting layer that coverts the white light into a light having acertain (e.g., predetermined) color or a color filter.

A protection layer may be disposed on the opposite electrode 285 and maycover and protect the OLED. An inorganic insulation layer and/or anorganic insulation layer may be used as the protection layer.

The spacer may be disposed between pixel regions in a display region DA.The spacer may be provided to maintain an interval between the substrate10 and the encapsulation unit 30 and to prevent display characteristicsfrom being degraded by external impacts.

The spacer may be provided on the pixel defining layer 29. The spacermay protrude from the pixel defining layer 29 toward the encapsulationunit 30.

In some embodiments, the spacer may be formed of the same material asthe material used to form the pixel defining layer 29 and by using thesame process as the process used to form the pixel defining layer 29.For example, the pixel defining layer 29 and the spacer may beconcurrently (e.g., simultaneously) formed by adjusting an amount ofexposure by using a halftone mask during an exposure process. However,the present invention is not limited thereto. The pixel defining layer29 and the spacer may be sequentially or separately formed and may beindependent structures formed of different materials.

The display device according to the present embodiment will now bedescribed with reference to FIG. 1.

As shown in FIG. 1, the display device according to the presentembodiment may be divided into the display area A/A in which the displayunit 20 emits light and an outer area O/A that is a remaining region(e.g., a region other than the display area NA) of the display device.

The display unit 20 may be provided in the display area A/A as shown inFIG. 1. The encapsulation unit 30 may be formed on the substrate 10throughout the display area NA and the outer area O/A such that theencapsulation unit 30 may cover the display unit 20.

The encapsulation unit 30 has a structure in which a plurality of thinfilm layers are stacked, such as a structure in which an inorganic layer31 and an organic layer 33 are alternately stacked.

Although a first inorganic layer 31 a, a first organic layer 33 a, and asecond inorganic layer 31 b are sequentially stacked on the display unit20 in FIG. 1, the number of thin film layers is not limited thereto. Theencapsulation unit 30 may be formed without restriction of the number ofthin film layers as long as the encapsulation unit 30 has the structurein which the inorganic layer 31 and the organic layer 33 are alternatelystacked.

The inorganic layer 31 may strongly prevent penetration of oxygen ormoisture to the display unit 20, and the organic layer 33 may absorbstress applied to the inorganic layer 31 to enhance flexibility.

The inorganic layer 31 may be a single layer or a multi-layer stackincluding metal oxide and/or metal nitride. For example, the first andsecond inorganic layers 31 a and 31 b may include SiN_(x), Al₂O₃, SiO₂,and/or TiO₂.

The organic layer 33 is formed of a polymer and may be a single layer ora multi-layer stack formed of, for example, polyethylene terephthalate,polyimide, polycarbonate, epoxy, polyethylene, and/or polyacrylate. Forexample, the organic layer 33 may be formed of polyacrylate. Forexample, the organic layer 33 may include a result of (e.g., may beformed by) polymerizing a monomer composition including adiacrylate-based monomer and/or a triacrylate-based monomer. The monomercomposition may further include a monoacrylate-based monomer. Themonomer composition may further include a well-known photoinitiator,such as trimethyl benzoyl diphenyl phosphine oxide (TPO), but thepresent invention is not limited thereto.

As shown in FIG. 1, a first dam 41 may be formed in the outer area O/Aof the substrate 10. The first dam 41 may be formed at an edge of thefirst organic layer 33 a and may be formed to have a height (e.g., apredetermined height) to prevent the first organic layer 33 a fromunintendedly spreading when the first organic layer 33 a is formed(e.g., the first dam 41 may be formed to contain the first organic layer33 a when the first organic layer 33 a is formed).

In some embodiments, the first dam 41 may be formed of the same materialas that of the pixel defining layer 29 and formed during the sameprocess as used to form the pixel defining layer 29. For example, thepixel defining layer 29 and the first dam 41 may be concurrently (e.g.,simultaneously) formed by adjusting an amount of exposure through anexposure process by using a halftone mask, but the present invention isnot limited thereto.

The first dam 41 may be formed on an upper portion of an ELVSS. As shownin FIG. 1, the first dam 41 may be formed toward the outside of theupper portion of the ELVSS.

The first and second inorganic layers 31 a and 31 b may be formed on aportion of the substrate 10 to cover the first dam 41. The first organiclayer 33 a may be formed at the inside of the display area NA and theouter area O/A in which the first dam 41 is formed.

In one embodiment, the outer area O/A may be divided into an inner unitB (e.g., an inner portion) in which the first organic layer 33 a isformed and an outer unit A (e.g., an outer portion) in which the firstdam 41 is formed and the first organic layer 33 a is not formed. Becausethe layers in the inner unit B are deposited in such a manner that anorganic layer has a uniform or substantially uniform thickness, althoughstress is applied to the inner unit B during a process of bending theouter area O/A, the stress is absorbed by the organic layer and, thus,flexibility may be securely provided to the inner unit B.

When a structure like the first organic layer 33 a is not formed in theouter unit A, stress may be wholly absorbed during the bending process,and accordingly, a crack may occur due to a tensile stress differencebetween the inner unit B and the outer unit A.

For example, an outer region of the display area NA may be bent to forma dead space D/S, and the entire the outer unit A and the inner unit B,in other words, the entire outer area O/A, may be bent to minimizeformation of the dead space D/S.

During the process, stress is applied to a substrate and upper elementsor layers thereon due to the bending. Thus, there may be a difference inthe stress applied to the inner unit B in which the organic layer isformed and the outer unit A in which the organic layer is not formed. Asdescribed above, the organic layer may act to absorb stress and ensureflexibility.

Therefore, if the formation of the dead space D/S is minimized, there isa concern that the crack may occur due to the stress difference betweenthe inner unit B and the outer unit A. If a region in which the deadspace D/S is formed increases to reduce a chance of the crack occurring,a size of the display device may be undesirably increased.

The display device according to the present embodiment may include asecond dam 43 and a stress relieving layer 50 as shown in FIG. 1, whichwill be further described in detail below.

The display device according to the present embodiment may furtherinclude the second dam 43 spaced from (e.g., spaced apart from) thefirst dam 41 (e.g., spaced by a predetermined distance) and provided atan outer region of the first dam 41 (e.g., an outer region of the firstdam 41 with respect to the display unit 20).

The second dam 43 may be formed at edges of the first inorganic layer 31a and the second organic layer 31 b as shown in FIG. 1.

In some embodiments, the second dam 43 may be formed of the samematerial as that of the first dam 41 and through the same process asused to form the first dam 41. However, the present invention is notlimited thereto.

The stress relieving layer 50 has a certain height and may be formed ina space (e.g., an area) between the first dam 41 and the second dam 43(e.g., in the outer unit A).

The stress relieving layer 50 may be formed of an organic material andmay be formed by being deposited to have the same or substantially thesame height as that of the first organic layer 33 a but is not limitedthereto.

The stress relieving layer 50 is formed of a polymer and may be a singlelayer or a multi-layer stack formed of, for example, polyethyleneterephthalate, polyimide, polycarbonate, epoxy, polyethylene, and/orpolyacrylate. For example, the stress relieving layer 50 may be formedof polyacrylate. For example, the stress relieving layer 50 may includea result of (e.g., may be formed by) polymerizing a monomer compositionincluding a diacrylate-based monomer and/or a triacrylate-based monomer.The monomer composition may further include a monoacrylate-basedmonomer, but the present invention is not limited thereto.

The stress relieving layer 50 may be formed of the same material as thatof the first organic layer 33 a and through the same process as used toform the first organic layer 33 a.

The second dam 43 may act as a dam to prevent the stress relieving layer50 from spreading to the outside of the substrate 10 when the stressrelieving layer 50 is formed (e.g., the second dam 43 may contain thestress relieving layer 50 when the stress relieving layer 50 is formed).

The stress relieving layer 50 may be formed by using various processingmethods. For example, the stress relieving layer 50 may be formedthrough inkjet processing in order to easily control spreading of at anedge thereof in some embodiments. However, a method of forming thestress relieving layer 50 is not limited thereto.

Thus, in some embodiments, the stress relieving layer 50 may be formedof the same organic material as that of the first organic layer 33 athrough inkjet processing to be between the first dam 41 and the seconddam 43 after forming the second dam 43.

The stress relieving layer 50 may be formed by being deposited to have acertain height like the first organic layer 33 a in order to reduce thestress difference between the inner unit B and the outer unit A.

Accordingly, when the outer area O/A is bent, the likelihood of a crackforming may be substantially reduced or prevent because the firstorganic layer 33 a absorbs stress applied to the inner unit B and thestress relieving layer 50 absorbs stress applied to the outer area O/A.

The display device according to the present embodiment may furtherinclude a protection film 60 provided below (e.g., at a lower portion orat a lower surface) of the substrate 10. The protection film 60 mayprotect the display device from an external impact during amanufacturing process and prevent penetration of moisture from the lowerportion of the substrate 10.

The protection film 60 may be attached to the lower portion of thesubstrate 10 by a thin adhesion layer. When the adhesion layer is usedto attach the protection film 60 to the lower portion of the substrate10, twisting of the substrate 10 may be effectively prevented.

The protection film 60 is positioned in the display area A/A. However,the protection film 60 may be positioned inside from an edge of thedisplay area NA by a certain length L.

The protection film 60 prevents the substrate 10 from being damaged whenthe substrate 10 is bent.

FIG. 3 is a schematic cross-sectional view illustrating a display deviceaccording to another embodiment of the present invention. The samereference numerals between FIGS. 1-3 denote the same elements and, thus,redundant descriptions may be omitted for brevity of description.

Differences between the display device according to the presentembodiment and the display device according to an embodiment of FIG. 1will be primarily described.

As shown in FIG. 3, a protection film 61 may be provided below (e.g., ata lower portion) of the substrate 10 in the display device according tothe present embodiment.

In one embodiment, the protection film 61 may be formed having a roundedupper edge.

During a process of bending the substrate 10, compressive stress isapplied to the lower portion of the substrate 10 due to contraction andtensile stress is applied to an upper portion of the protection film 61due to expansion.

During a process of manufacturing the display device, a bending processmay be repeatedly performed due to an external force, and when stressthat is greater than a breaking stress is applied to the display device,the display device may be damaged.

In one embodiment, the rounded upper edge of the protection film 61 maybe formed to relieve stress that occurs in the lower portion of thesubstrate 10 and the upper portion of the protection film 61.

FIG. 4 is a schematic cross-sectional view illustrating a display deviceaccording to another embodiment of the present invention. The samereference numerals between FIGS. 1-4 denote the same elements and, thus,redundant descriptions may be omitted for brevity of description.

As shown in FIG. 4, a notch 110 (e.g., a notch unit) may be formed in alower surface of the substrate 10 of the display device according tosome embodiments of the present invention.

As described above, during a process of manufacturing the displaydevice, compressive stress is applied to the lower portion of thesubstrate 10 due to contraction. To remove or reduce the compressivestress, the display device may have the notch 110 in the lower portionof the substrate 10.

The notch 110 may be formed in the lower surface of the substrate 10 inthe form of a groove having a certain height and width. The height andwidth of the notch 110 are not limited, and a shape of the notch 110 isnot also limited to the illustrated shape.

The notch 110 may be formed in the lower surface of the substrate 10 andmay be formed in a region to which compressive stress is most applied orconcentrated. Because the notch 110, that is, the groove having acertain shape, is formed in the lower surface of the substrate 10,although a bending process is performed, compressive stress applied tothe lower surface of the substrate 10 may be reduced. As a result, thedisplay device is prevented from being damaged.

The notch 110 having a triangular shape may be formed in the lowersurface of the substrate 10 of the display device according to thepresent embodiment. A width and a height of the notch 110 may havevarious values according to an anticipated bending degree but are notlimited thereto. However, the height of the notch 110 may have a smallervalue than that of the thickness of the substrate 10.

FIG. 5 is a schematic cross-sectional view illustrating a display deviceaccording to another embodiment of the present invention. The samereference numerals between FIGS. 1-3 and 5 denote the same elements and,thus, redundant descriptions may be omitted for brevity of description.

The display device according to the present embodiment is primarilydifferent from the display device according to the embodiment of FIG. 4in that a notch 130 has a different shape than the notch 110 of FIG. 4,and thus, differences between these embodiments will be primarilydescribed for convenience of description.

As shown in FIG. 5, the display device according to the presentembodiment may be formed such that the notch 130 formed in the lowersurface of the substrate 10 has a circular shape (e.g., a semicircularshape).

A radius of the notch 130 having the circular shape may have variousvalues according to an anticipated bending degree but is not limitedthereto. The radius of the notch 130 may have a smaller value than thatof the thickness of the substrate 10.

The notch 130 may be formed in the lower surface of the substrate 10 andmay be formed in a region to which compressive stress is most applied orconcentrated. Because the notch 130, that is, a groove having a certainshape, is formed in the lower surface of the substrate 10, although abending process is performed, compressive stress applied to the lowersurface of the substrate 10 may be reduced. As a result, the displaydevice is prevented from being damaged.

FIG. 6 is a schematic cross-sectional view illustrating a display deviceaccording to another embodiment of the present invention. The samereference numerals between FIGS. 1-3 and 6 denote the same elements and,thus, redundant descriptions may be omitted for brevity of description.

The display device according to the present embodiment is primarilydifferent from the display device according to the embodiment of FIG. 4in that a notch 150 has a shape different from the notch 110, and thus,differences between these embodiments will be primarily described forconvenience of description.

As shown in FIG. 6, the display device according to the presentembodiment may be formed such that the notch 150 having a rectangularshape is formed in the lower surface of the substrate 10.

A width and a height of the notch 150 having the rectangular shape mayhave various values according to an anticipated bending degree but arenot limited thereto. However, the height of the notch 150 may have asmaller value than that of the thickness of the substrate 10.

The notch 150 may be formed in the lower surface of the substrate 10 andmay be formed in a region to which compressive stress is most applied orconcentrated. Because the notch 150, that is, a groove having a certainshape, is formed in the lower surface of the substrate 10, although abending process is performed, compressive stress applied to the lowersurface of the substrate 10 may be reduced. As a result, the displaydevice is prevented from being damaged.

As described above, according to the one or more of the above-describedembodiments of the present invention, a dead space region of a displaydevice is reduced or minimized while a crack is prevented from formingin a substrate.

It should be understood that the exemplary embodiments described hereinshould be considered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each embodimentshould typically be considered as available for other similar featuresor aspects in other embodiments unless specifically indicated otherwise.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopeof the present invention as defined by the following claims and theirequivalents.

What is claimed is:
 1. A display device comprising: a substrate; adisplay unit on the substrate and configured to emit light; a firstinorganic layer on the display unit; a first organic layer on the firstinorganic layer; a second inorganic layer on the first organic layer,the second inorganic layer directly contacting the first inorganic layeroutside of the first organic layer; a first dam overlapping with atleast a portion of the first organic layer; a second dam spaced from thefirst dam and at an outer region of the first dam with respect to thedisplay unit; a second organic layer above the first dam; and aconductive layer overlapping with at least a portion of the secondorganic layer; wherein respective edges of the first inorganic layer andthe second inorganic layer are located between the first dam and thesecond dam.
 2. The display device of claim 1, wherein the conductivelayer comprises a ELVSS.
 3. The display device of claim 2, wherein thefirst dam overlaps with the ELVSS.
 4. The display device of claim 1,wherein the second organic layer comprises an organic material.
 5. Thedisplay device of claim 1, wherein the second organic layer comprises asame material as that of the first organic layer.
 6. The display deviceof claim 1, wherein the second organic layer is formed using an inkjetprocess.
 7. The display device of claim 1, further comprising aprotection film below the substrate.
 8. The display device of claim 7,wherein the protection film is spaced from a display area and is insidea display area of the display device.
 9. The display device of claim 7,wherein an upper edge of the protection film is rounded.
 10. The displaydevice of claim 7, wherein the substrate has a notch, and wherein thenotch is spaced from an edge of the protection film.
 11. The displaydevice of claim 1, wherein the second organic layer overlaps with thefirst inorganic layer between the first dam and the second dam.
 12. Thedisplay device of claim 1, wherein the second organic layer overlapswith the second inorganic layer between the first dam and the seconddam.
 13. The display device of claim 1, wherein the second dam overlapswith at least a portion of the second organic layer.
 14. The displaydevice of claim 1, wherein the conductive layer, the first dam, and thesecond organic layer comprise a region overlapping in a directioncrossing the substrate.